Aerosolization of COVID-19 and Contamination Risks During Respiratory Treatments

Beyond asthma and chronic obstructive pulmonary disease (COPD), inhalation therapy is a mainstay in the management of bronchiectasis, cystic fibrosis, and pulmonary artery hypertension. Several US Food and Drug Administration off-label indications for inhalational medications include hypoxia secondary to acute respiratory distress syndrome (ARDS) and intraoperative and postoperative pulmonary hypertension during and following cardiac surgery, respectively.^1-11 Therapeutic delivery of aerosols to the lung may be provided via nebulization, pressurized metered-dose inhalers (pMDI), and other devices (eg, dry powder inhalers, soft-mist inhalers, and smart inhalers).¹² The most common aerosolized medications given in the clinical setting are bronchodilators.¹²

Product selection is often guided by practice guidelines (Table 1), consideration of the formulation’s advantages and disadvantages (Table 2), and/or formulary considerations. For example, current guidelines for COPD state that there is no evidence for superiority of nebulized bronchodilator therapy over handheld devices in patients who can use them properly.² Due to equivalence, nebulized formulations are commonly used in hospitals, emergency departments (EDs) and ambulatory clinics based on the drug’s unit cost. In contrast, a pMDI is often more cost-effective for use in ambulatory patients who are administering multiple doses from the same canister.

The World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) recommend droplet and contact precautions for all patients suspected or diagnosed with novel coronavirus-19 (COVID-19).^13,14 Airborne precautions must be applied when performing aerosol-generating medical procedures (AGMPs), including but not limited to, open suctioning of the respiratory tract, intubation, bronchoscopy, and cardiopulmonary resuscitation (CPR). Data from the severe acute respiratory syndrome (SARS-CoV) epidemic suggest that nebulization of medication is also an AGMP.^15-17

Institutions must ensure that their health care workers (HCWs) are wearing appropriate personal protective equipment (PPE) including gloves, long-sleeved gowns, eye protection, and fit-tested particulate respirators (N95 mask) for airborne procedures and are carefully discarding PPE after use.^13,14 Due to severe shortages in available respirators in the US supply chain, the CDC has temporarily modified WHO recommendations. Face masks are now an acceptable alternative to protect HCWs from splashes and sprays from procedures not likely to generate aerosols and for cleaning of rooms, although there is no evidence to support this decision.

Internationally, HCWs are falling ill with COVID-19. Data from Italy and Spain show that about 9% to 13% of these countries’ cases are HCWs.^18,19 Within the US, the Ohio health department reports approximately 16% of cases are HCWs.²⁰ It is possible that 20% of frontline HCWs will become infected.²¹ Evolving laboratory research shows that COVID-19 remains viable in aerosols for up to 3 hours postaerosolization, thus making aerosol transmission plausible.²² Nebulizers convert liquids into aerosols and during dispersal may potentially cause secondary inhalation of fugitive emissions.²³ Since interim CDC infection control guidance is to allow only essential personnel to enter the room of patients with COVID-19, many facilities will rely on their frontline nursing staff to clean and disinfect high-touch surfaces following routine care activities.²⁴

Achieving adequate fomite disinfection following viral aerosolization may pose a significant problem for any patient receiving scheduled doses of nebulized medications. Additionally, for personnel who clean rooms following intermittent drug nebulization while wearing PPE that includes a face mask, protection from aerosolized virus may be inadequate. Subsequently, fugitive emissions from nebulized medications may potentially contribute to both nosocomial COVID-19 transmission and viral infections in the medical staff until proven otherwise by studies conducted outside of the laboratory. Prevention of infection in the medical staff is imperative since federal health care systems cannot sustain a significant loss of its workforce.